On The Brain (Fall 2013): The Wonders of the Middle-Aged Brain

As if people reaching their middle years didn't have enough to keep them awake at night—mortgage payments, job demands, the angst of teenage children - a study by French and British researchers last year concluded that our brains start to decline around age 45, smack in the prime of middle age. Although the study did find that certain innate skills, like memory and reasoning speed, begin to slow between our forties and sixties, the news was not all bad: the study also found that, compared with brain performance in Gen Xers and millennials, middle-aged adult brains perform certain functions better.

According to this study, published in the British Medical Journal, our memory, reasoning, and comprehension skills - collectively known as cognitive function—begin to worsen as we enter middle age, not around age 60 as previous studies concluded. Bruce Yankner, an HMS professor of genetics and neurology, notes there is indeed evidence from formal testing that short-term memory starts to decline in our forties and fifties. What’s not clear, however, is whether that decline has an impact on day-to-day functioning.

In a 2004 Naturestudy, Yankner examined how human brains change between ages 26 and 106. From ages 26 to 40, brains showed similar patterns of wear and tear, as well as low levels of gene damage. As expected, more genetic damage appeared in the brains of individuals in their seventies. The finding that surprised Yankner appeared in some people between ages 40 and 70, the heart of middle age. The brains of some individuals had gene patterns similar to those found in younger people, while the brains of other individuals were more like those of older people and thus more susceptible to damage. That, says Yankner, suggests that some people’s brains age more quickly during middle age.

"Our study showed that genes involved in memory start to fall in expression around age 40," says Yankner. "It’s very gradual and very individual, but there are biological changes in gene regulation that start in middle age due, in part, to stress and damage."